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Selective nickel-iron separation from atmospheric leach liquor of a lateritic nickel ore using the para-goethite method

Basturkcu H., Acarkan N.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 1

212--226

EN

The presence of iron in pregnant leach solutions (PLS) is a common problem, and is generally removed using jarosite, goethite, hematite or para-goethite precipitation methods. Although these methods are successfully applied, significant amounts of nickel can be lost. In this study, iron precipitation was performed on a PLS obtained from agitation leaching of a lateritic nickel ore under atmospheric conditions using the para-goethite method. The PLS contained 2.62 g/dm3 Ni, 54.28 g/dm3 Fe and 0.14 g/dm3 Co. During the precipitation tests the effect of pH, time, temperature, and metal concentration were investigated. The influence of the key points, temperature and metal concentration, on nickel loss was explained in reference to SEM and XRD analyses. Ultimately, selective nickel and iron separation was achieved with complete iron precipitation and only 1.2% Ni loss.

2

Separation of nickel and iron from lateritic ore using a digestion – roasting – leaching – precipitation process

Basturkcu H., Acarkan N.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

564--574

EN

This paper investigates extraction of nickel and iron from a lateritic nickel ore from the Caldag region of Manisa in Turkey. The ore sample contains 1.2% Ni, 24.77% Fe and 0.062% Co. The process applied includes digestion with 40 wt-% sulfuric acid at 200 C for 60 min, roasting at 700 C for 15 min, leaching with water for 30 min at 1:5 solid/liquid ratio (by weight) and precipitation of the remaining iron at pH 3 and 60 C. In order to improve nickel and cobalt extractions using the digestion-roasting- leaching-precipitation process (DRLP), Na2SO4 addition in the roasting stage was examined. Under the optimum conditions and in the presence of Na2SO4, 86.2% Ni and 94.2% Co extractions were obtained with almost zero iron content. As a result, 2.07 g dm-3 Ni, 0.12 g dm-3 Co and 0.05 g dm-3 Fe could be achieved in the pregnant leach solution within nearly 2.5 hours.

3

Leaching behaviour of a turkish lateritic ore in the presence of additives

Basturkcu H., Acarkan N.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 1

112--123

EN

This paper investigates the dissolution mechanism of a lateritic nickel ore from the Caldag Region of Manisa in Turkey. The ore sample contained 1.2% Ni, 24.8% Fe, and 0.062% Co. The optimum leaching conditions were found to be temperature 80 oC, particle size -74 μm, H2SO4 concentration 200 g/dm3, solids ratio (by weight) 10% and leaching duration 8 h. The extractions of 98.2% Ni, 98.6% Fe and Co 98.9% were obtained under these conditions. Additionally, the effects of additional substances such as NaCl, Na2S2O5, Na2SO4, and KCl were investigated in order to decrease the leaching duration. The results showed that the additives accelerated the leaching kinetics and achieved nearly the same nickel and cobalt extractions at the end of 4 h compared to the results obtained after 8 h without the additives. If the additives containing chlorine were used, it was determined that the iron extraction showed no increase, although both the nickel and cobalt extractions increased.

4

Effect of silver, nickel and copper cyanides on gold adsorption on activated carbon in cyanide leach solutions

Sayiner B., Acarkan N.

Physicochemical Problems of Mineral Processing

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2014

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Vol. 50, iss. 1

277--287

EN

The effect of Ag, Ni and Cu cyanides on gold adsorption on activated coconut carbon in cyanide leach solutions was investigated by synthetic cyanide leach solutions containing gold and other metal cyanides. According to the adsorption tests Ag remarkably reduces the gold adsorption on activated carbon by competing with gold to adsorption sites. When the Ag concentration in solution increases up to 200 ppm the carbon adsorption method for gold recovery becomes inapplicable. Ni has an effect on gold adsorption on activated carbon, however even at as high concentrations of Ni as 250 ppm residual Au in solution is still below 1 ppm. Cu addition up to 300 ppm does not affect the gold loading significantly. According to the adsorption test studies, it is concluded that the metal-cyanides diminish the gold adsorption on activated carbon by adsorbing themselves and competing with gold. When the metals are present in the leach solution all together with gold, they also prevent adsorption of themselves as well as gold. Thus, when Au, Ag, Ni and Cu are present in solution simultaneously, the adsorption of all these metals decreases. The adsorption results were modeled by Fleming k,n adsorption kinetic model.